In your Velocity templates you may need to access some parts of your API / constants. Here is one simple way to do this (there are other ways).

Here are the steps:

  1. Create a class that extends
  2. Register this action in
  3. Enjoy!

1. Create a class that extends

This class should be put in a Liferay hook. This Action class will be executed by Liferay once your server has started.

In the below code snippet we add to velocity context:

  • one Java object (use a singleton if it’s a util class) : instance of MyUtilClass
  • one Java const called “MY_CONST” with the value “WORLD”
public void run(final HttpServletRequest request, final HttpServletResponse response) throws ActionException {

  Map <String, Object> vmVariables = (Map <String, Object> ) request.getAttribute(WebKeys.VM_VARIABLES);

  if (vmVariables == null) {
    vmVariables = new HashMap <String, Object> ();
    vmVariables.put("myUtilClass", getMyUtilClassWrapper());
    vmVariables.put("MY_CONST", "WORLD");
  request.setAttribute(WebKeys.VM_VARIABLES, vmVariables);

private static final MyUtilClass MY_UTIL_CLASS;

private static MyUtilClassWrapper getMyUtilClassWrapper() {
  if (MY_UTIL_CLASS == null) {
    MY_UTIL_CLASS = new MyUtilClass();
  return MY_UTIL_CLASS;

2. Register this action in

Then build & deploy your hook.

Liferay will execute this action in the class MainServlet, check Liferay source code if you want to have a better understanding of the logic.

3. Enjoy!

Now in your velocity templates you can use your Java object and your Java constant:


There are other ways to do it, I think that this one is the most simple one.